How Can I Remove Null or Undefined Attributes from a JavaScript Object?

Remove Blank Attributes from an Object in JavaScript

In JavaScript, objects can have properties that are undefined or null, which can clutter up code and make it more difficult to work with. To remedy this, we can remove these blank attributes from an object using various techniques.

ES10/ES2019

These methods use the introduction of the Object.fromEntries() method:

• A one-liner: let o = Object.fromEntries(Object.entries(obj).filter(([_, v]) => v != null));
• Same as above but as a function: function removeEmpty(obj) { return Object.fromEntries(Object.entries(obj).filter(([_, v]) => v != null)); }
• A recursive version to remove items from nested objects: function removeEmpty(obj) { return Object.fromEntries( Object.entries(obj) .filter(([_, v]) => v != null) .map(([k, v]) => [k, v === Object(v) ? removeEmpty(v) : v]) ); }

ES6/ES2015

• A mutating one-liner: Object.keys(obj).forEach((k) => obj[k] == null && delete obj[k]);
• A non-mutating version: let o = Object.keys(obj) .filter((k) => obj[k] != null) .reduce((a, k) => ({ ...a, [k]: obj[k] }), {});
• Similar to above, written as a function: function removeEmpty(obj) { return Object.entries(obj) .filter(([_, v]) => v != null) .reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {}); }
• A recursive function to handle nested objects: function removeEmpty(obj) { return Object.entries(obj) .filter(([_, v]) => v != null) .reduce( (acc, [k, v]) => ({ ...acc, [k]: v === Object(v) ? removeEmpty(v) : v }), {} ); }

ES5/ES2009

• A functional non-recursive version: function removeEmpty(obj) { return Object.keys(obj) .filter(function (k) { return obj[k] != null; }) .reduce(function (acc, k) { acc[k] = obj[k]; return acc; }, {}); }
• A recursive functional version: function removeEmpty(obj) { return Object.keys(obj) .filter(function (k) { return obj[k] != null; }) .reduce(function (acc, k) { acc[k] = typeof obj[k] === "object" ? removeEmpty(obj[k]) : obj[k]; return acc; }, {}); }

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